"Atomic Blonde" opens with Charlize Theron's MI6 agent, Lorraine Broughton, sitting naked on the edge of an ice-filled bathtub, bruised from head to toe, fumbling to get more cubes into her tumbler than onto the floor, before downing a sizable swig of vodka to numb her pain.

Subsequent moments of such genuine vulnerability, unfortunately, prove too few and far between, and the movie's ambition of melding spy-thriller drama with gloriously violent action flick falls apart when the former fails to keep pace with the latter.

Largely set in 1989 Berlin, mere days before the fall of the wall, Broughton is dispatched to meet up with station chief David Percival (James McAvoy) and retrieve a master list of allied field agents' identities taken from a murdered colleague, the sale of which to Russian parties could "extend the Cold War for 40 years." She's also given a secondary assignment to ferret out and dispatch the notorious double agent "Satchel," whose information leaks have proven a source of embarrassment to British intelligence.

Director David Leitch, a former stuntman who helmed the Keanu Reeves-starring revenge action hit "John Wick," delivers the brutal, highly stylized goods again.

Mere moments after touching down in Germany, Broughton is fending off one baddie with a high heel while forcing another into crashing and flipping the car they're riding in. And a nearly-10-minute, apparently uncut fight-and-flight sequence is an eye-popping wonder, made all the better for not portraying Broughton as some invincible warrior or her foes as susceptible to being rendered unconscious by a single blow. The scene of bloodied-up, punch-drunk combatants staggering about, falling down to gather themselves, then going at it again is sullied only by the too-convenient trope of some makeshift weapon always being conveniently within arm's length when needed most (hello, corkscrew!).

Meanwhile, after displaying her badass side as Imperator Furiosa in "Mad Max: Fury Road," Theron doubles down in "Atomic Blonde," convincingly holding her own against an assembly line of bigger, physically stronger henchmen, and — just as important — proving as capable of absorbing a beating as delivering one.

Alas, every time the pace slows, so too does the film's momentum.

The overly long and unnecessarily circuitous plot, based on Antony Johnston's "The Coldest City" graphic novel and credited to screenwriter Kurt Johnstad, reduces Theron to a flat affect every time she's not trading blows with some wholly unmemorable villain. Even her seduction of French operative Delphine Lasalle (Sofia Boutella) comes across as cold and calculating.

There are fleeting moments of personality shown, such as the under-her-breath invectives directed at her MI6 boss (Toby Jones) and an assisting CIA chief (John Goodman) during a post-mission debriefing. And she's at her most engaging when paired with the livewire McAvoy, whose Percival has cultivated a wildman persona labeled "feral" by one of their handlers, but which causes Broughton, annoyed by the put-on, to snap, "Drop the 'I don't know which way is up' act already!" Indeed, the levity inherent in their pairing — "Don't shoot! I've got your shoe!" — makes the decision to frequently split them up as frenemies most unfortunate.

All along the way, curious decisions rob the film of the dramatic build it strains to achieve, be it the shallow pool of potential candidates for "Satchel" or the overused juxtaposition of murder soundtracked by '80s pop songs (a man is beaten to death with his skateboard by a KGB agent to the tune of Nena's "99 Luftballoons"). And there's a decent chance you'll see the big twist coming.

Of course, there's just as decent a chance you won't anticipate the twist on the twist, but even that's a bit disappointing, as it robs the first of a potentially heavy impact in favor of a trite resolution.

Despite those shortcomings, in the end, "Atomic Blonde" is still fun when it simply allows Theron to go nuclear on the bad guys.

'Atomic Blonde'

Charlize Theron proves a convincingly capable badass again, but the spy-thriller components can't match the frenetic action sequences.

Where • Theaters everywhere.

When • Opens Friday, July 28.

Rating • R for sequences of strong violence, language throughout and some sexuality/nudity.

Running time • 114 minutes.

This image released by Focus Features shows Charlize Theron, left, and Sofia Boutella in
This image released by Focus Features shows Charlize Theron, left, and Sofia Boutella in "Atomic Blonde." (Jonathan Prime/Focus Features via AP)